Recently, use of the portable telephone is spreading rapidly and it is replacing the public telephone, and those who are conversing over the portable telephones can be seen wherever one goes. However, in a place where other persons are around the portable telephone, for example in a train or a store, there is a possibility that the other persons will feel uncomfortable hearing the conversations through the portable telephone. In an aircraft or a hospital, sensitive electronic instruments may malfunction because of electromagnetic radiation from the portable telephone. Moreover, if a user of a pacemaker approaches the portable telephone emitting radio waves, it is possible that the pacemaker could be affected, and endanger a human life.
On the other hand, the portable telephone manufactured in the recent years has the functions meeting various demands which do not directly relate to its intrinsic function, namely the telephonic communication or the electronic mail (the communicative mode, hereinafter). Explaining concretely, the portable telephone is also used for the various purposes, such as a telephone directory, a calendar, a game, a music-reproducer, an electronic memo pad, a voice recorder, etc. (the noncommunicative mode, hereinafter) in addition to its intrinsic function. Furthermore, now that the portable telephone begins to be related to the internet closely, it is expected that the functions of applying the portable telephone to the internet will be added thereto.
However, even in a state that the multi functional portable telephone is functioning in the noncommunicative mode, if both transmitting and receiving circuits arc operational, the functional mode of the portable telephone is changed over to the communicative mode from the noncommunicative mode responding to a call from the base station, which is a grave incommodity for the user. Accordingly, it is desirable to provide a portable telephone having such a function that the use in the communicative mode is inhibited if the noncommunicative mode is once selected. The portable telephone having the aforementioned function is disclosed in Japanese Patent Applications, Laid-Open, No. 11-308163.
FIG. 1 shows a structure of a conventional portable telephone.
This portable telephone is composed of an antenna 101 for transmitting and receiving radio signals, a radio unit 102 which converts a data to be transmitted into a radio signal, and converts a received radio signal into a data, a base band-processing unit 103 which converts a voice signal to be transmitted into a specified data series and outputs it to the radio unit 102, and converts a received data series supplied from the radio unit 102 into an audio signal, a central processing unit (CPU, hereinafter) 104 for controlling the whole system, a memory 105 which stores program codes for stopping a communicative function as well as the other program codes and data of a telephone directory and of an electronic memo pad, an input unit 106 for inputting data in accordance with operations of keys, a display 107 for displaying telephone numbers, a microphone 108 for converting a voice signal into an audio signal, a speaker 109 for converting the audio signal into an aural signal, a control unit 110 for controlling whole electric circuits in accordance with instructions inputted from the CPU 104, a battery 111 serving as a power supply, a power supply-controlling unit 112 for controlling supplies of electric power generated by the battery 111 to various structural elements, and a stop-confirming unit 1131 which outputs a stop-requiring signal for requiring the control unit 110 to stop the communicative function when a specified key of the input unit 106 is pushed down.
In FIG. 1, real lines show electrical signal line, and broken lines show electrical power supply lines, where the power supply lines 113, 114, 115, 116, 117, 118, 119 are respectively connected with the radio unit 102, the base band-processing unit 103, the control unit 110, the CPU 104, the memory 105, the input unit 106, and the display 107.
In the system shown in FIG. 1, when a power supply-activating key (not shown) of the input unit 106 is closed in a stand-by state, the control unit 110 instructs the power supply-controlling unit 112 to supply electric power. The power supply-controlling unit 112 supplies electric power generated by the battery 111 to various structural elements via the power supply lines 113 to 119 in accordance with the instructions outputted from the control unit 110. Thereafter, the CPU 104 starts to operate and interchange intercommunication signals (a radio controlling function for setting up, maintaining and interchanging radio channels, a mobile controlling function for registering and certifying positions of vehicles, calling and interruptions of mutual communications, etc.) with a base station covering the portable telephone at a fixed interval via the control unit 110, the radio unit 102, and the antenna 101, and prepares for requirements related to transmissions and receptions of the messages.
When the specified key in the input unit 106 is pushed down, the stop-confirming unit 1131 outputs the stop-requiring signal for requiring the control unit 110 to stop the system shown in FIG. 1 from functioning in the communicative mode. When the control unit 110 receives the stop-requiring signal from the stop-confirming unit 1131, the control unit 110 outputs a stop-requiring flag or an interruption signal so that the CPU 104 executes the instruction to stop the system from functioning in the communicative mode. When the CPU 104 receives the stop-requiring flag from the control unit 110, the CPU 104 instructs the control unit 110 to stop supplies of electric power to the radio unit 102 and to the base band-processing unit 103. The control unit 110 reads a data meaning that the communicative mode is being stopped from the memory 105 and output it to the display 107. When an icon representing a stoppage of the communicative mode is displayed on the display 107, the user seeing the display 107 can recognize that the communicative mode is being stopped. As mentioned in the above, since the user can cancel the communicative mode of the portable telephone of his own accord at any time, he can use the portable telephone in the noncommunicative mode (as the watch or the telephone directory, for instance) even in a place where the conversation through the portable telephone is prohibited.
However, according to the aforementioned portable telephone, in case that the user uses it in the noncommunicative mode in a condition that the specified key is not pushed down and the communicative mode is not canceled, the communicative mode is still functioning. Accordingly, if the user forgets to push down the specified key and is called up by the base station, there arises inconvenience that the communicative mode is activated, and the portable telephone cannot be used in the noncommunicative mode.
In such a case, since no one but the user recognizes whether the portable telephone is functioning in the noncommunicative mode or not, and the other persons around him cannot know the functional mode of the portable telephone, the user is obliged to refrain from using the portable telephone, even in case that he desires to use it in the noncommunicative mode in a place where the use of the portable telephone is prohibited or repressed.
However, if the transmitting and receiving systems are so constructed that the communicative made is stopped form functioning and the other persons around the user can recognize clearly that the portable telephone is functioning in the noncommunicative mode, the use of the portable telephone in the noncommunicative mode will be permitted in a place where the use of the portable telephone is prohibited or repressed, such as in the train or in the hospital.